The present invention relates generally to an easy opening, reclosable carton, and more particularly to a sift-proof easy opening, reclosable paperboard folding cartons and to blanks from which such cartons are made.
For the purposes of the following specification and claims, the dimensions of "length" and "width" referred to the easy opening end of the closed erected carton, with the length being the maximum dimension of the end and the width (sometimes called "thickness") being the minimum dimension of the end. The dimension of "depth" (sometimes called "height") refers to the remaining dimension of the carton. The dimensions of length L, width W and depth D are illustrated in FIGS. 1 and 2 for a top-opening carton. While the drawings, specification and claims define the present invention in the context of a top-opening carton, clearly the same principles are applicable to a side opening carton.
U.S. Pat. No. 4,718,557 discloses a carton structure providing an easy opening feature, yet being relatively strong prior to the initial opening to maintain product integrity during shipping, handling and sale, and a reclosable feature to maintain product freshness and/or prevent product contamination or spillage after the initial opening.
Easy opening cartons in general, including those described in U.S. Pat. No. 4,718,557, are subject to sifting. "Sifting" refers to the process by which fine particulate matter such as flour, soap powders, cereal and the like which the carton is intended to hold escape from the interior of the carton to the exterior of the carton. In an easy opening carton, sifting is most pronounced where the minor end panel is an exterior end panel overlying the major end panels, and negligible where the minor end panel is an interior end panel underlying one or both of the major end panels. The particulate matter escapes through the gap between the exterior minor end panel and the major end panels which it overlies and, more particularly, through the gap between the foldline or vertex of the minor end panel and the side panel from which it extends and the major end panels. The finer the particulate matter within the carton, relative to the gap, the greater the likelihood and extent of sifting. The sifting may occur during storage, transport or handling of the unopened sealed carton, especially when the carton is turned upside down or on its side.
To the extent that the escaping particulate matter lands on the shipping carton, retail store shelf or the like, it reduces the initial packed weight of the carton (so that the customer may not be receiving as much of the product as he is paying for) and, depending upon the nature of the product, may create an undesirable mess within the shipping container or, worst yet, on the retail store shelf. Even where the escaping product remains exclusively on the outer surface of the carton, it may create a messy appearance or an irregular or otherwise undesirable feel to the carton, thereby rendering it unacceptable to prospective purchasers. In any case, the visible evidence of sifting is generally sufficient to discourage a potential purchaser from purchasing the carton in question.
Accordingly, it is an object of the present invention to provide an easy opening, reclosable carton which is sift-resistant and preferably substantially sift proof.
Another object is to provide a blank from which such a carton may be formed.